The growth hormone secretory profile in acromegalics will be studied by sampling every 5 minutes for twenty-four hours. This frequency of sampling is necessary to adequately characterize pulsatile GH release in normal subjects; and now this technique will be applied to acromegalic patients. The GH response to a growth hormone releasing factor bolus will also be determined. Excessive GH secretion in acromegaly can be characterized by abnormalities in either basal GH release and/or number, amplitude or width of pulses.